Improvement in head-blocks for saw-mills



PATENT OFFICE.

JOHN W. PARSONS, OF OWENTON, KENTUCKY.

IMPROVEMENT IN HEAD-BLOCKS FOR SAW-MILLS.

Specification forming part of Letters Patent No. 57,180, dated August 14, 1866.

To all whom it may concern:

Be it known that I, JOHN W. PARSONS, of Owenton, Owen county, Kentucky, have invented a new and useful Improvement in Head- Blocks of Saw-Mills; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawings, making part of this specification.

My invention relates to devices for enabling the simultaneousor separate setting forward oi' the knees of two or more sawmill headlolocks, and for the release ot' one or more knees from the setting motion, all of said motions being under control ofthe sawyer from a single position.

Figure 1 is a perspective view ota pair of head-blocks embodying myinvention. Fig. 2. is a top view of the head-blocks without the knees.

A represents a part of the log-carriage. B B are head-blocks attached thereto, and surmounted by ways or tracks b b for the support and guidance of knees O C. Projecting from the sole ofeach knee is a double ratchet-rack, D.

E is a rock-head, pivoted at e to the carriage or head-block, and armed with two pairs of pawls, Ff Ff, of which one pawl, for-f', of each pair projects beyond its fellow, F or F', halt' the pitch of the rack-teeth.

Springs G G projecting inwardly from the head-blocks, serve to press the pawls toward the rackD and cause th em to en gagein theteeth thereof. Both rock-heads E, and through them the pawls F f F' f', are capable of being simultaneously operated by a lever, H, acting through links I Il and rod J.

In order to enable the release of one or both the knees from the setting mechanism. l have provided in each headblock a cam, K or K', which, being partially rotated by means of lever L or L and rods L or l', presses apart two tongues, M M', having studs man', which, bearing outwardly against projections N from the pawls, serve to hohl said pawls entirely clear of the racks, and thus enable the withdrawal or retraction ot' the liberated knee or the working of the other knee alone.

It is intended that the points of the several pawls shall be so adjusted relatively to each other as for the points ofone pair to engage in their appropriate teeth midway ofthe intervals ofen gagement ofthe opposite pair, and in this way, although the teeth of the rack itself may be one inch apart and strong in proportion, a pawl is ready to en gage every fourth of an inch, and in this way the adjustment of the knee in setting forward may be of any desired nicety.

I claim herein as new and of my invention- 1. The setting mechanism consisting ofthe double rack D and pawls Ff Ff', capable of simultaneous or separate action, substantially as set forth.

2. The cam K, lever L, rod l, and tongue M, adapted for the optional release otl both or either head-blocks, in the manner explained.

In testimony ot' which invention I hereunto set my hand.

JOHN W. PARSONS.

Witnesses J. SIMON, JAIVLEs H. Doni/IAN. 

